Courts Follow Science in California and EU to Give Cosmetics Win

Recent court decisions in California and the EU rejecting mandated hazard warnings for titanium dioxide serve as a stark reminder that such requirements may be vulnerable to legal challenge when they’re supported by disputed scientific conclusions.

The August rulings also show that, despite growing anti-chemical sentiments among consumers and lawmakers, courts across the globe are demanding that regulation be based on sound scientific evidence.

The US District Court in the Eastern District of California concluded Aug. 12 that the results of bioassays evaluating the carcinogenic potential of TiO2 in animal models didn’t support conclusions that TiO2 definitively causes cancer in humans. As a result, they were inadequate to justify compelled speech, such as a Proposition 65 warning.

The European Court of Justice had reached a similar conclusion Aug. 1, finding the available scientific evidence didn’t support classifying TiO2 as Category 2 (suspect human) carcinogen and upheld an annulment of associated hazard labeling requirements as initially mandated by the European Commission.

Carcinogen in Cosmetics

California’s Office of Environmental Health Hazard Assessment listed TiO2 as a carcinogen under Proposition 65 in 2011.

The addition of TiO2 was triggered after the International Agency for Research on Cancer’s classification of the substance as “possibly carcinogenic to humans.”
Titanium dioxide is one of a handful of substances with a listing that specifies a specific state of the substance—in this case, applying only to “airborne, unbound particles of respirable size.” As such, under the law, TiO2 that isn’t airborne, is bound, or is greater than 10 microns in size wouldn’t require a Proposition 65 warning, regardless of exposure.

The Personal Care Products Council, a trade association for the cosmetic industry, sued over the TiO2 warning requirements for cosmetic and personal care products. The challenge built on the precedent of similar cases that invalidated Proposition 65 warning requirements for glyphosate and acrylamide.

In those cases, trade associations for wheat farmers and the food industry, respectively, successfully challenged the state by arguing Proposition 65 warnings for glyphosate and acrylamide in food violated companies’ First Amendment rights as false and misleading compelled speech due to inadequate toxicological evidence of carcinogenicity.

Eastern District of California Chief Judge Troy Nunley reached a similar conclusion, finding that requiring Proposition 65 warnings for TiO2 in cosmetic and personal care products violated the First Amendment as false or misleading compelled speech—and handed a victory to the cosmetic industry.

Unsupported Conclusions

The European Commission categorized TiO2 in powdered form with 1% or more particles less than or equal to 10 microns in diameter, as a Category 2 carcinogen in 2019. The decision had the support of the European Chemicals Agency or ECHA, and the French National Agency for Food, Environmental and Occupational Health and Safety, among others.

A Category 2 designation is warranted when human or animal studies reveal limited evidence of carcinogenicity but establish a strong causal relationship between the agent and an increased incidence of malignant neoplasms. In reaching a Category 2 designation for TiO2, the ECHA had relied heavily on animal studies.

Various manufacturers, importers, downstream users, and suppliers of titanium dioxide soon challenged this classification by alleging the aforementioned studies were inadequate to support such conclusions.

The General Court of the EU agreed that the references studies weren’t adequate to support the European Commission’s actions, and annulled the classification in 2022.

The European Court of Justice upheld that ruling last month, concluding that the regulatory decision in classifying TiO2 as a suspect human carcinogen was flawed. It cited ECHA’s methodological errors, such as failing to account for the agglomeration and density of nano-sized particles, leading to a mischaracterization of the exposure level.

The court reaffirmed that the pivotal studies failed to demonstrate an intrinsic carcinogenic property of TiO2, as the observed effects were likely due to non-specific lung overload, which don’t reflect typical human exposures.

In doing so, it emphasized the need for a transparent and justified assessment amid scientific controversy.

Case Similarities

In both the California and EU cases, courts reviewed the data underlying the classification of TiO2 as a suspect human carcinogen and found them to be lacking.

The primary study that led to the hazard classification by the International Agency for Research on Cancer and the ECHA showed increased lung tumors under “lung overload” conditions. Lung overload refers to exceeding a threshold where the lungs’ natural ability to clear or exhale inhaled particles is overwhelmed, which leads to particle accumulation and subsequent adverse effects due to the accumulation.

However, both courts agreed the relevance of the core animal studies to human health outcomes under relevant exposure conditions was far from decisive.

Combining this with the lack of human epidemiological evidence of carcinogenicity—and the frequent conflation of assessments of hazard (a potential for harm) versus risk (a likelihood of harm occurring under a specific set of circumstances)—each court found the weight of toxicological evidence inadequate to justify regulatory actions implying definite human carcinogenicity.

The court decisions in California and the EU are victories for the entire TiO2 supply chain, but the long-term significance may prove to be immeasurable. They provide a glimmer of hope that science may rule the day.

This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law, Bloomberg Tax, and Bloomberg Government, or its owners.

Author Information

Natalie Rainer is a partner in K&L Gates’ healthcare and FDA practice group, focusing on laws affecting the food, cosmetic, and broader consumer product industries.

Peter Coneski, Ph.D., is a senior scientific adviser in K&L Gates’ healthcare and FDA practice.

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